This International Standard specifies requirements and provides guidance for design, testing, installation and commissioning of heating, ventilation, air-conditioning and pressurization systems and equipment on all offshore production installations for the petroleum and natural gas industries that are ? new or existing, ? normally occupied by personnel or not normally occupied by personnel, ? fixed or floating but registered as an offshore production installation. For installations that can be subject to “Class” or “IMO/MODU Codes & Resolutions”, the user is referred to HVAC requirements under these rules and resolutions. When these requirements are less stringent than those being considered for a fixed installation, then it is necessary that this International Standard, i.e. requirements for fixed installations, be utilized.